The working principle of switching power supply
1. The AC power input is rectified and filtered into DC;
2. Control the switching tube through high-frequency PWM (pulse width modulation) or pulse frequency modulation (PFM), and add that DC to the primary of the switching transformer;
3. The secondary side of the switching transformer induces a high-frequency voltage, which is rectified and filtered to supply the load;
4. The output part is fed back to the control circuit through a certain circuit to control the PWM duty cycle to achieve the purpose of stable output.
